Cryptic mycotic abdominal aortic aneurysms: diagnosis and management

The incidence of cryptic mycotic abdominal aortic aneurysms has relatively increased since antibiotic therapy has become available. The causative organism is the salmonella group in about 50 per cent of cases. This diagnosis should be strongly entertained in patients with fever of unknown origin, vague abdominal pain, and progressive appearance of a pulsatile abdominal mass. Aortography may be helpful in establishing the diagnosis. Some postoperative graft infections may be due to unrecognized cryptic mycotic infection of the aorta and not from external contamination, as previously supposed. Construction of an axillofemoral bypass graft through clean tissue is advised for the successful treatment of the grossly infected infrarenal aortic aneurysm. Three surviving patients with cryptic mycotic abdominal aortic aneurysms are added to the sixteen surviving patients already reported in the literature.     

Human immunodeficiency virus and infected aneurysm of the abdominal aorta: Report of three cases

Three patients who were seropositive for human immunodeficiency virus underwent surgery for infected aneurysm of the abdominal aorta. Fever and abdominal pain were the principal presenting clinical features. None of the patients had any opportunistic infections or endocarditis. In two cases, a ruptured aneurysm was demonstrated radiographically. In the remaining case, sonograms were diagnostic. The organisms responsible weresalmonella, Hemophilus influenzae, andMycobacterium tuberculosis. In two cases, the infectious origin was evidenced by bacteriologic examination of the aortic wall, which revealed the presence ofSalmonella enteritidis and Koch's bacillus. AlthoughHemophilus influenzae was not found in the aortic wall of the remaining case, the infectious origin of the aneurysm was established because preoperative blood cultures were positive for this pathogen, and pathohistologic examination of the specimen showed destruction associated with leukocyte infiltration of the aneurysmal wall. An in situ prosthetic graft replacement protected by omentum was performed in all three cases. Antibiotic therapy was continued for several weeks. All patients are well with follow-up ranging from 10 to 21 months. Infectious aneurysm associated with human immunodeficiency virus seropositivity results in bacterial infestation of an atheromatous aorta. Infected phenomena are promoted by cellular immunodeficiency. Surgery was justified in these cases because of the immediate threat of rupture.Presented at the Annual Meeting of the Société de Chirurgie Vasculaire de Langue Française, June 21–22, 1991, Marseille, France.     

Arterial Infections in the New Millenium: An Old Problem Revisited

The natural history of infected aneurysms or arterial infections is characterized by rapid expansion leading to rupture, pseudoaneurysm formation, and sepsis. Treatment options include in situ grafting either with prosthetic or autogenous grafts or with cryopreserved allografts (CPAs), resection of the aneurysm with remote bypass grafting, and ligation. The purpose of this study was to review our recent experience with these infections and to present long-term follow-up with in situ CPAs. From January 2000 through June 2005, we treated nine patients with infected aneurysms and one patient with an infection without aneurysm formation. The infection involved the infrarenal abdominal aorta in six patients and the femoral artery in three patients. One patient had an infected splenic artery aneurysm. Aortic rupture occurred in five of the six patients with infected aortas. Two of the three patients with infected femoral aneurysms presented with recurrent hemorrhage. Of the six patients with aortic infections, five were treated with in situ CPAs. One patient was treated with aortic resection and axillofemoral grafting. Two patients with femoral aneurysms were treated with in situ CPAs, and the third patient underwent aneurysm resection and prosthetic grafting through the obturator foramen. The patient with the splenic aneurysm underwent combined valve replacement, aneurysm resection, and splenectomy. Three of the six patients with aortic infections died postoperatively, all of whom were septic at presentation. The cause of death in these three patients was multiple organ failure in two and overwhelming sepsis in one. The three survivors are alive and well with up to 5-year follow-up. The three patients with infected femoral aneurysms are alive and well with follow-up extending to 44 months. The patient with the splenic aneurysm is doing well. No recurrent infections have been noted among the survivors. The CPAs have remained structurally intact in all. The mortality rate among patients with abdominal aortic infections remains high and is likely related to their preoperative septic state. In situ grafting with CPAs appears to be a reasonable treatment option for arterial infections. CPAs appear to maintain their structural integrity and to be resistant to recurrent infection.     

The management of the infected aortic prosthesis: A current decade of experience

Purpose: Newer approaches to the patient with an infected aortic graft are available. We reviewed a recent 10-year experience with a more traditional approach to evaluate its outcome in the 1990s.Methods: From January 1983 to January 1993, 27 patients with an aortic graft infection were treated at our institution. There were 18 paraprosthetic infections, eight graft enteric erosions, and one aortoduodenal fistula. The involved bypasses included 20 aortofemoral (74%), five aortoiliac (18%), and two aortic tube grafts (8%). Nineteen aortic replacements were done originally for aneurysmal disease (70%). We reviewed the outcome of each patient treated as it related to the method of management. The therapy for graft infection consisted of aortic graft removal and axillofemoral bypass in 20 patients (74%), treatment by an in situ method in four patients (15%), excision of an aortofemoral limb and extraanatomic bypass in two patients (7%), and extraanatomic bypass alone in one patient (4%). In the group treated by graft removal and extraanatomic bypass, four patients (20%) had staged operations (extraanatomic bypass followed by interval aortic graft removal), nine (45%) had single operations with extraanatomic bypass preceding graft removal, and seven (35%) had single operations with graft removal preceding extraanatomic bypass.Results: The 30-day operative mortality rate was 3.7%. There were no instances of aortic stump blowout. The 3-year primary patency rate for axillofemoral bypass limbs was 80.2%, and the secondary patency rate was 87.4%. No limbs were lost as a result of ischemic complications. There was one late amputation for an unrelated problem.Conclusions: The results of alternate approaches to the management of patients with infected aortic grafts were equivalent both in terms of perioperative mortality and morbidity rates in this group of patients. Complete excision of the aortic graft with axillofemoral bypass provided a satisfactory long-term outcome and remains the standard with which other approaches must be compared. (J VASC SURG 1994;19:844-50.)     

The contrary position to the nonresective treatment for abdominal aortic aneurysm

The operative mortality rate for abdominal aortic aneurysm resection remains high (20% to 66%) for high-risk patients. The high-risk factors are severe cardiac, respiratory, and renal insufficiency and morbid obesity. Those advocating the alternative nonresective treatment of aneurysm thrombosis and axillofemoral bypass grafts have reduced the operative mortality rate to between 0% and 7%. However, in a collective series of 87 patients, there was a mortality rate of 10.3% in the patients with aortic aneurysms treated by the nonresective method and an incidence of reoperation for complications of axillofemoral graft of 31.0%. Many of these patients had subsequent operations and/or radiologic procedures to complete the process of aneurysm thrombosis (23.0%). Because there is an increasing trend toward this method of treatment, we reviewed our experience with the conventional aneurysm resection in a similar group of patients. Of 105 consecutive patients, 19 qualified as high risk. One patient died, resulting in an operative mortality rate of 5.2%. Cerebral, cardiac, and renal morbidity was transient and subsequent operations were not required. Eighteen patients were discharged as well. In the remaining 86 patients, one died, resulting in an operative mortality rate of 1.2%. The mortality rate for the entire series was 1.9%. Indications for the nonresective treatment appear to be increasing by the addition of other risk factors. This trend is of concern. We believe that there are limited indications for the treatment of aortic aneurysms without resection. However, the procedure should not be offered lightly as an alternative form of treatment.     

Secondary arterio-enteric fistulae: a surgical challenge

Ten cases of secondary arterio-enteric fistulae are described. There were nine graft enteric fistulae and one fistula involving the aortic suture line following elective resection of an infected graft. Only four of the patients initially received prophylactic antibiotics (single dose) at the original aortic reconstruction, and the vascular suture line had only been protected in two. Eight patients presented with bleeding and two with groin abscesses. One patient died before operation. Graft resection was undertaken in all patients and organisms were grown from six of eight grafts cultured. No patient died during operation but one died after 3 days. Axillofemoral bypass grafts were constructed in seven patients (four immediately after resection of prosthetic grafts and three within 4 days of operation). Only three of the eight patients who survived operation are still alive; two died of a ruptured aorta and one from a recurrent fistula. Two patients died of other causes. Four of five axillofemoral grafts in surviving patients subsequently occluded.     

Long-term outcome after treatment of aortic graft infection with staged extra-anatomic bypass grafting and aortic graft removal

OBJECTIVE: The purpose of this study was to determine long-term outcome in patients with infected prosthetic aortic grafts who were treated with extra-anatomic bypass grafting and aortic graft removal. METHODS: Between January 1989 and July 1999, 36 patients were treated for aortic graft infection with extra-anatomic bypass grafting and aortic graft removal. Extra-anatomic bypass graft types were axillofemoral femoral (5), axillofemoral (26; bilateral in 20), axillopopliteal (3; bilateral in 1) and axillofemoral/axillopopliteal (2). The mean follow-up was 32.3 +/- 4. 8 months. RESULTS: Four patients (11%) died in the postoperative period, and two patients died during follow-up as a direct consequence of extra-anatomic bypass grafting and aortic graft removal (one died 7 months after extra-anatomic bypass graft failure, one died 36 months after aortic stump disruption). One additional patient died 72 months after failure of a subsequent aortic reconstruction, so that the overall treatment-related mortality was 19%, whereas overall survival by means of life table analysis was 56% at 5 years. No amputations were required in the postoperative period, but four patients (11%) required amputation during follow-up. Twelve patients (35%) had extra-anatomic bypass graft failure during follow-up, and six patients underwent secondary aortic reconstruction (thoracobifemoral [2], iliofemoral [2], femorofemoral [2]). However, with the exclusion of patients undergoing axillopopliteal grafts (primary patency 0% at 7 months), only seven patients (25%) had extra-anatomic bypass graft failure, and only two patients required amputation (one after extra-anatomic bypass graft removal for infection, one after failure of a secondary aortic reconstruction). Furthermore, primary and secondary patency rates by means of life table analysis were 75% and 100% at 41 months for axillofemoral femoral grafts and 64% and 100% at 60 months for axillofemoral grafts. Only one patient required extra-anatomic bypass graft removal for recurrent infection, and only one late aortic stump disruption occurred. CONCLUSIONS: Staged extra-anatomic bypass grafting (with axillofemoral bypass graft) and aortic graft removal for treatment of aortic graft infection are associated with acceptable early and long-term outcomes and should remain a primary approach in selected patients with this grave problem.     

对感染性腹主动脉瘤治疗的再认识

感染性腹主动脉瘤（IAAA）是临床灾难性疾病,治疗困难,病死率高。手术治疗的目标是清除病灶、防止瘤体的破裂以及保持血流通道。尽早足疗程抗生素的使用是治疗的基础,包括原位重建及腋股旁路术的传统外科手术符合外科治疗原则,但清除感染病灶后的原位重建术后移植物感染率较高,腋股旁路术后有可能出现移植物阻塞及主动脉残端破裂等严重并发症。腔内治疗与外科处理原则不尽相符,但临床现有的资料证实高龄不能耐受开放手术的病例仍然适用。后腹膜旁路术能有效减少移植物感染并保持移植物通畅,是较合理的IAAA的手术方式。     

Axillofemoral Bypass Graft in a Spinal Cord Injured Patient with Impending Gangrene

ABSTRACT

The axillofemoral bypass graft, an extra-anatomic graft, connects the axillary artery to the femoral artery and is used in the treatment of significant aortoiliac occlusive disease in poor-risk patients. A common indication for axillofemoral bypass is a “hostile abdomen” (postoperative adhesions, neoplasms or radiation). Less frequent indications are aortic mycotic aneurysm, infected aortobifemoral bypass graft, aortoduodenal fistula, inflammatory aneurysm and extensive retroperitoneal fibrosis.

Spinal cord injured patients with peripheral arterial disease have two problems: 1) lack of premonitory symptoms (absence of claudication, paresthesias or rest pain) and 2) difficulty preventing pressure sores in the already poorly perfused limb. Indications for arterial reconstructive surgery are more drastic in this set of patients (impending gangrene and/or ischemic ulcers). Many spinal cord injured patients have sources of possible contamination (cystostomy and/or colostomy) which make intra-abdominal clean surgery impossible.

We present a spinal cord injured patient with a permanent cystostomy and impending gangrene of the left foot. He underwent a left axillofemoral bypass graft and had a good postoperative course.

We conclude that axillofemoral bypass graft is a good alternative for limb salvage in the spinal cord injured patient, especially when there is a source of possible contamination (colostomy and/or cystostomy) that would interfere with more common bypass grafting. The role of the noninvasive vascular laboratory for early detection of vascular disease is emphasized. (J Am Paraplegia Soc: 17; 171–176)     

Ruptured Abdominal Aortic Aneurysms due to <Emphasis Type="Italic">Salmonella</Emphasis>, not of <Emphasis Type="Italic">typhi</Emphasis> Species

Ruptured aortic aneurysms due to Salmonella not of typhi species are rare and associated with high morbidity and mortality. We present three patients with Salmonella-infected ruptured aortic aneurysms successfully treated with an in situ prosthetic bypass graft. One patient had a saccular aneurysm at the infrarenal aorta and two patients had fusiform aneurysms at the aortic bifurcation. All the patients were treated with wide debridement of the infected aortic tissue followed by in situ graft replacement and long-term systemic antibiotic therapy. The method of revascularization, in situ bypass or extraanatomic bypass, remains controversial. On the basis of our clinical experience and recent literature focusing on more than 10 cases, in situ bypass reconstruction may be a feasible surgical technique for Salmonella-infected ruptured aortic aneurysm.     

Use of rifampin-soaked gelatin-sealed polyester grafts for in situ treatment of primary aortic and vascular prosthetic infections

BACKGROUND: In situ treatment of artery/graft infection has distinct advantages compared to vessel excision and extra-anatomic bypass procedures. Based on animal studies of a rifampin-soaked, gelatin-impregnated polyester graft that demonstrated prolonged in vivo antibacterial activity, this antibiotic-bonded graft was used selectively in patients for in situ treatment of low-grade Gram-positive prosthetic graft infections or primary aortic infections not amenable to excision and ex situ bypass. METHODS: In a 5-year period (1995-1999), 27 patients with prosthetic graft infection (aortofemoral, n = 18, femorofemoral, n = 3; axillofemoral, n = 1) or primary aortic infection (mycotic aneurysm, n = 3; infected AAA, n = 2) underwent excision of the infected vessel and in situ replacement with a rifampin soaked (45-60 mg/ml for 15 min) gelatin-impregnated polyester graft. All prosthetic graft infections were low grade in nature, caused Gram-positive bacteria (Staphylococcus epidermidis, 16; Staphylococcus aureus, 5; Streptococcus, 1), and were treated electively. Patients with mycotic aortic aneurysm presented with sepsis and underwent urgent or emergent surgery. RESULTS: Two (8%) patients died-1 as a result of a ruptured Salmonella mycotic aortic aneurysm and the other from methicillin-resistant S. aureus infection following deep vein replacement of an in situ replaced femorofemoral graft. No amputations or late deaths as the result of vascular infection occurred in the 25 surviving patients. Two patients developed recurrent infection caused by a rifampin-resistant S. epidermidis in a replaced aortofemoral graft limb and were successfully treated with graft excision and in situ autogenous vein replacement. Eighteen patients remain alive and clinically free of infection after a mean follow-up interval of 17 months. CONCLUSIONS: In situ replacement treatment using a rifampin-bonded prosthetic graft for low-grade staphylococcal arterial infection was safe, durable, and associated with eradication of clinical signs of infection. Failure of this therapy was the result of virulent and antibiotic-resistant bacterial strains.     

In situ repair of mycotic abdominal aortic aneurysms with rifampin-bonded gelatin-impregnated Dacron grafts: A preliminary case report

Treatment of mycotic aortic aneurysm by excision and extraanatomic bypass is difficult to apply when the infectious process involves the visceral arteries. On the basis of experimental studies in our laboratory that demonstrated prolonged antistaphylococcal activity of rifampin-bonded, gelatin-impregnated Dacron grafts after implantation in the arterial circulation, this conduit was successfully used for in situ replacement of a native aortic infection in two patients. Both patients had fever, leukocytosis, abdominal or back pain, and a computed tomographic scan that demonstrated contained rupture of a mycotic aneurysm. Preoperative computed tomography guided aspiration and culture of periaortic fluid from one patient grew Staphylococcus aureus. Treatment consisted of prolonged (6 weeks) culture-specific parenteral antibiotic therapy, excision of involved aorta, oxychlorosene irrigation of the aortic bed, and restoration of aortic continuity by in situ prosthetic replacement. A preliminary right axillobifemoral bypass was performed in the patient who had an infection involving the suprarenal and infrarenal aorta. In both patients intraoperative culture of aorta wall recovered S. aureus. Patients were discharged at 20 and 21 days. Clinical follow-up and computed tomographic imaging of the replacement graft beyond 10 months after surgery demonstrated no signs of residual aortic infection. In the absence of gross pus and frank sepsis, the use of an antibiotic-bonded prosthetic graft with antistaphylococcal activity should be considered in patients who have arterial infections caused by S. aureus when excision and ex situ bypass are not feasible. (J Vasc Surg 1996;24:472-6.)     

Infected Aneurysms of the Infrarenal Abdominal Aorta: Diagnostic Criteria and Therapeutic Strategy

Salmonella infection and two patients with spondylitis) had positive preoperative blood cultures. Salmonella was the most common microorganism (27%). Anaerobes accounted for 16%. In situ replacement was performed in 13 patients including three procedures performed under emergency conditions with frank purulent infection. Extraanatomic bypass was performed in five patients. Early postoperative death occurred in two patients (11%) due to septic complications (rupture of aortic anastomosis in one patient and rupture of aortic stump in one patient). All surviving patients underwent prolonged antibiotic therapy for at least 6 weeks. Overall mortality secondary to infected aneurysm was 16%. Infection of the aortic graft occurred in four patients (38%) including two patients with Salmonella infection and one patient with spondylitis. One patient developed a false anastomotic aneurysm 6 months postoperatively and was treated by in situ arterial allograft replacement. Postoperative blood cultures were positive in two patients presenting spondylitis and infection of the aortic prosthesis occurred in one of these patients. In addition to rupture, poor prognostic factors included spondylitis and Salmonella infection that were found to greatly enhance the risk of postoperative graft infection following in situ reconstruction.     

Management of infected aortoiliac aneurysms

A 30-year retrospective review identified 13 patients treated for infected aneurysms of the abdominal aorta or iliac arteries, for an overall incidence of 0.65%. A constellation of clinical findings led to the correct preoperative diagnosis in 11 (85%) of 13 patients. Treatment methods included resection and in situ replacement grafting in seven patients, resection and extra-anatomic bypass in five patients, and resection-ligation in one patient. Four (31%) of 13 patients died within 30 days of operation, three of whom died of rupture. Overall, good results were achieved in five patients (38%), while poor results were noted in the remaining eight patients (62%). The determinants of outcome were aneurysm location or rupture, the presence of established infection, and the virulence of the infecting organism. In 10 (77%) of the 13 aneurysms, Salmonella species, Bacteroides fragilis, Staphylococcus aureus, and Pseudomonas aeruginosa accounted for all deaths, ruptures, and suprarenal aneurysm infections. These data suggest that patients with primary infections of the abdominal aorta or iliac arteries continue to present with advanced infections or aneurysm rupture that result in a high mortality.     

New concepts in the use of axillofemoral bypass grafts

Over a four-year period, 52 patients underwent axillofemoral bypass operations. Indications for operation were divided into three groups: those that were performed emergently (aortoenteric fistula, graft infection, and leaking aortic aneurysm), those performed electively for aneurysm, and those for ischemia. Operative procedures were categorized as follows: axillofemoral bypass alone, axillofemorofemoral bypass with the proximal femorofemoral anastomosis being graft to graft, or axillofemorofemoral bypass with the femorofemoral anastomosis to either a transected proximal common femoral artery or superficial femoral artery distal to the axillofemoral anastomosis. Thirty-three percent of the unilateral axillofemoral grafts failed, while only 14% of the axillobifemoral grafts failed. There was a further difference between the two methods of femorofemoral grafting with 22% failure in the former group but no failures in the latter.     

Management of Infected Grafts and Aneurysms of the Aorta

Seventeen patients treated for infected grafts (11/17) or aneurysms (6/17) of the aorta between 1998 and 2003 were reviewed to evaluate our experience with aortic infection. The causative organisms were identified in 12 patients (71%), with 5 (29%) having methicillin-resistant Staphylococcus aureus. A periaortic abscess occurred in eight patients, and all of them were associated with infected grafts. Surgical treatment included cryopreserved allograft replacement in eight patients, prosthetic graft replacement in four patients, and drainage with or without omental wrapping in five patients. One patient was still hospitalized at the end of the study period. Five patients with infected grafts died after the operation during the initial hospitalization. No early mortality occurred in the aneurysm group. The early mortality rate was 31% for all patients, 50% for the graft group, and 63% for patients with a periaortie abscess. Another patient with an infected aneurysm died of arrhythmia after discharge from the initial hospitalization, Ten patients are still alive without evidence of reinfection. The early mortality rate for patients with infected aortic grafts is higher than that for those with infected aneurysms, especially when a periaortic abscess accompanies them. However, the late outcome is favorable, with no reinfection or late treatment-related deaths.     

Arteritis due to Salmonella with aneurysm formation: two cases.

Although arterial infection due to Salmonella is rare, it remains one of the most common causes of primary mycotic aneurysms. The presentation is one of sepsis, cultures positive for Salmonella and rapid expansion or rupture of the aneurysm. The authors' experience at Victoria Hospital, London, Ont., includes two cases of aneurysms infected with Salmonella--one aneurysm of the aorta and the other of the common femoral artery. Both patients were treated by excision of the aneurysm, extra-anatomic reconstruction in an area remote from the infected field and long-term administration of appropriate antibiotics. One patient was alive and well 36 months after resection. The other died of multiple organ failure 10 days after resection. From a review of the English and French literature since 1948, 64 cases of abdominal aortic aneurysms infected with Salmonella were found; half of the patients survived the perioperative period. The diagnosis of mycotic aneurysm must be considered in any patient with an aneurysm and culture specimens positive for Salmonella. The authors favour wide débridement of the infected aneurysm with extra-anatomic reconstruction. This view is supported by a review of the literature. The appropriate antibiotic therapy is bactericidal rather than bacteriostatic.     

A ten-year experience with bacterial aortitis

Twenty-one patients with bacterial aortitis were treated in four institutions over a 10-year period. Clues to the diagnosis were a pulsatile mass; fever; positive blood culture; CT scan revealing aortic nodularity, an aneurysm of irregular configuration, or air in the aortic wall; and angiography revealing a lobulated aneurysm. The most commonly identified organisms were Salmonella and Staphylococcus. Excision with in situ repair was performed in nine patients; 11 patients underwent extraanatomic bypass grafting with aortic ligation. In situ graft repair was performed when the infected aorta could be removed entirely or when the thoracic or suprarenal aorta was involved. Axillofemoral bypass grafting was used when infection was extensive. There were eight disease-related deaths. No graft infections were encountered in patients who survived.     

Infection of artificial vascular prostheses. Case reports

Four patients with prosthetic graft infection are presented. In 3 patients infection occurred in a Dacron aortobifemoral graft. In all 4 patients the infection originated at the femoral anastomoses. In 2 patients the entire aortofemoral graft was removed; one patient died of septicaemia and the other required an above-knee amputation. In 1 patient partial removal of the graft limb proved successful after a femorofemoral bypass using an autogenous venous graft. Above-knee amputation was performed in a further patient after removal of an infected axillofemoral graft. Staphylococcus was consistently isolated from the infected grafts in all the patients.     

A case of successfully resected abdominal aortic aneurysm complicated by arteriocolic fistula

A 80 year-old man was admitted to our hospital with profuse rectal bleeding. Two weeks prior to admission he was diagnosed as having abdominal aortic aneurysm when he had first herald of rectal bleeding. Aortoenteric fistula was strongly suspected and patient underwent emergency operation. Bilateral axillofemoral bypass were first constructed in order to avoid contamination in hte peritoneal cavity. On laparotomy aneurysm was contaminated because of arteriocolic fistula and resection of aortoiliac aneurysm and Hartmann procedure were performed. In the postoperative course, formation of an intra-abdominal abscess, obstruction of the left axillo-femoral bypass graft and enlargement of a residual aneurysm occurred. The prolonged antibiotic therapy was successful and additional repair operations were performed. Abdominal aortic aneurysm complicated with arteriocolic fistula is a rare but lethal disease. To our knowledge, only 13 cases have been reported in the literature including our case. Eleven patients were operated but only 3 survived. Construction of an extra-anatomic bypass, avoidance of an anastomosis in unprepared bowel and aggressive use of antibiotics are recommended because fecal contamination to the aneurysm is inevitable in most cases.